Let me start by saying I like text. I can read about 5 times as fast as I can listen, so it is efficient for me; writing clearly takes many times longer than verbally extemporising on the same subject, as you go back and revise and clarify (at least, you do if you respect your readers, and want to keep their attention).
Small Pieces Loosely Joined took David Weinberger the best part of a year to write, and I read it through in 3 hours or so, very efficiently absorbing his thoughts and insights.
Conversely, voicemail is appalling - it is easy to leave, but it can take 2 listenings to extract a phone number from a two minute rambling message.
Text is great at describing ideas; sound at emotions; pictures at providing overviews of complex data. In each case to do it well takes much effort, but it can be satisficed if there is a conversation—a one to one dialog going on. An IM chat can cope with mis-spellings and bad grammar; a phone call with long pauses and poor word choice, a whiteboard and pen handed back and forth saves hours of drawing, but if you want more than a few people to get it at once, and if you want it to stand for a while, you need to put the work in.
Weblogs fit neatly between magazine articles and email on the continuum that runs from books to instant messaging. I'm not sure where the multimedia messages Ted Shelton likes fit into the image continuum from Fine art to whiteboard doodles or where the audio weblogs that Adam Curry wants fit between recorded performances and voicemail.
Last night I went to see Jewel at The Mountain Winery. Sitting there alone with her guitar, she carried the 500 or so of us there with her through the performance, telling self-deprecating stories, inviting requests, even having a 'stalker' fan pick a song, and then got him to stand next to her and hold the lyrics up as she couldn't remember them as it was so obscure. Catch the show if you can. And her Soul City Cafe project sounds interesting too.